I recently purchased an old bowl-back mandolin. I found an exact replica on Reverb, leading me to believe it is an American Conservatory mandolin. There are no markings anywhere on the instrument. I took it to my luthier and he insisted it is a greek bouzuki and put bouzuki strings on it (D'Addario - nickel-plated steel) and tuned it to CFAD.
I still feel that it is an American Conservatory mandolin, based upon reviewing differences between the two instruments. I am a beginner